Frequency ↔ Wavelength Calculator
Convert frequency to wavelength or wavelength to frequency using the wave equation v = fλ. Calculate electromagnetic wavelengths for RF and wireless signals, or use a custom wave speed for other types of waves and propagation media.
Frequency Wavelength Calculator
Enter frequency or wavelength and select the appropriate units and wave speed.
Frequency and Wavelength Formula
Frequency and wavelength are inversely related when the wave speed is fixed. Increasing frequency produces a shorter wavelength, while decreasing frequency produces a longer wavelength.
RF Signals
In RF engineering, wavelength is commonly used to determine antenna dimensions, transmission line behavior and electromagnetic propagation.
For a fixed propagation speed, higher-frequency RF signals have shorter wavelengths.
Frequency
Frequency describes how many complete cycles of a periodic wave occur each second and is measured in hertz.
1 Hz represents one cycle per second, while 1 MHz represents one million cycles per second.
Wavelength
Wavelength is the physical distance between corresponding points on successive cycles of a wave.
It is commonly expressed in meters, centimeters, millimeters, micrometers or nanometers.
Common RF Wavelengths
The following examples use the speed of light in vacuum, 299,792,458 m/s. Practical propagation conditions can change the effective wavelength.
| Frequency | Wavelength | Approx. Length | Common Area |
|---|---|---|---|
| 100 kHz | 2,997.9 m | ~3.0 km | LF |
| 1 MHz | 299.8 m | ~300 m | MF |
| 10 MHz | 29.98 m | ~30 m | HF |
| 100 MHz | 2.998 m | ~3 m | VHF |
| 433 MHz | 0.692 m | ~69.2 cm | ISM / RF |
| 868 MHz | 0.345 m | ~34.5 cm | ISM / RF |
| 915 MHz | 0.328 m | ~32.8 cm | ISM / RF |
| 2.4 GHz | 0.1249 m | ~12.49 cm | Wi-Fi / ISM |
| 5.8 GHz | 0.0517 m | ~5.17 cm | Wi-Fi / ISM |
| 10 GHz | 0.02998 m | ~3.0 cm | Microwave |
Worked Examples
Example 1: 1 GHz Signal
Calculate the wavelength of a 1 GHz electromagnetic signal in vacuum.
The wavelength is approximately 29.98 cm.
Example 2: 2.4 GHz Signal
Calculate the wavelength of a 2.4 GHz electromagnetic signal.
The wavelength is approximately 12.49 cm. This scale is useful when considering antenna dimensions and RF circuit geometry.
Example 3: 433 MHz
A 433 MHz RF signal is commonly used in low-power wireless applications.
The free-space wavelength is approximately 69.24 cm.
Example 4: Find Frequency
Suppose an electromagnetic wave has a wavelength of 0.5 meters in vacuum.
The corresponding frequency is approximately 599.6 MHz.
Why Wave Speed Matters
Electromagnetic Waves
In vacuum, electromagnetic waves propagate at exactly defined speed 299,792,458 m/s.
In practical environments, propagation can be affected by the surrounding medium and material properties.
Waves in Materials
The same frequency can have different wavelengths in different materials because wave speed changes.
This is especially important for transmission lines, dielectric materials, optical fiber, PCB substrates and waveguides.
Transmission Lines
The physical wavelength on a transmission line is affected by its propagation velocity.
Designers therefore often use a velocity factor rather than assuming that the signal always travels at the speed of light in vacuum.
PCB and RF Design
At sufficiently high frequencies, circuit dimensions become significant compared with the wavelength.
This is one reason RF PCB traces, antennas and transmission-line structures require careful consideration of wavelength.
Frequency, Wavelength and Antenna Design
Antenna dimensions are often expressed as fractions of a wavelength. Common starting points include quarter-wave and half-wave structures, although practical antenna dimensions depend on geometry, dielectric effects, loading and the surrounding environment.
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